Copying duplicate songs into itunes

Good afternoon Crackberry nation, a simple question for you, and I do apologize if this has been answered elsewhere.

Whenever I hookup my Z30 to my Laptop and sync it with itunes it always copies duplicate songs into my library? Is there a way to stop this? Or is there way to only have one way sync ie so the Z30 can't copy songs into itunes? There is another problem with this as well and that even though I have my ringtones saved in the ringtone folder they still copy over to my itunes library.

If you're using BlackBerry Link to move the files, just stop. Instead, use the option to just drag and drop the files onto your device or SD Card by enabling mass storage mode. BlackBerry Link sucks at transferring music and often misses album art, creates duplicates and messes up file names.